'calcareous region. 



4S 



this countiy from the Tenessee to the St. Lawrence, 

 between the mountains and the Missisippi, has for 

 its nucleus an immense stratum, of limestone, disposed 

 nearly in a horizontal direction, in laminx of one or 

 more inches thick, of a close smooth grain, and ge- 

 nerally of a grey colour. In the north the limestone 

 is of the crystallized kind, called primitive. 



It is shallpwest on the risings and heights, where it 

 occasionally does not exceed six or eight inches. 

 This circumstance, as well as the laminated structure 

 of the stone, evidently indicate an anterior opera- 

 tion of the waters of the ocean. 



In the country about Pittsburg on the Ohio, in the 

 county of Green Briar on the Kanhaway, and 

 throughout Kentucky, this fundamental stratum is 

 found on boring ; and it is seen bare in the beds of 

 all the rivers and brooks of Kentucky, from the 

 Kanhaway to the falls or rapids of the Ohio near 

 Louisville. 



From Louisville to White River, where it ab- 

 ruptly terminates, Mr. Volney likewise found all the 

 rivers and brooks flowing over the bare limestone 

 stratum of Kentucky. Some American travellers, 

 on seeing his specimens, have assured him, that the 

 liolston, or north branch of the Tenessee, had a si- 

 milar bed. 



The rocks that form the falls or rapids of the Ohio 

 below Louisville belong to this greiit limestone stra- 

 tum, on the surface of which many petrifactions 

 Iiave been collected at low water, but they were 

 brought thither, and not imbedded in it.* Mr. Vol- 



* ^ee tbe accoimt of tkc mcr ©Mo for a (jorrectioaof this error. 



